Among the 182 damaging storm reports from over the weekend were 12 that included tornadoes, from the Rockies into the Plains.
Flash flooding was reported in parts of Arkansas as Little Rock saw more than 4 inches of rain on Saturday, a new daily record for the city. Other parts of the state got more than half a foot of rain.
That system is likely to deliver severe storms into the Midwest on Monday -- with threats of damaging winds, a few tornadoes, flashing flooding or hail -- and then move farther East on Tuesday.
Dangerous heat and humidity should continue on Monday throughout the South, where many places will feel like triple digits.
Heat alerts have been issued for 13 states -- and some parts of the region may feel like 115 degrees because of the humidity.
The dangerous heat in the South is expected to continue into Tuesday.